This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (35) Citing Articles via Google Scholar Google Scholar Articles by Farkas, D. L. Articles by Malkin, S. Search for Related Content PubMed PubMed Citation Articles by Farkas, D. L. Articles by Malkin, S. Agricola Articles by Farkas, D. L. Articles by Malkin, S.

Articles

Cold Storage of Isolated Class C Chloroplasts

Optimal Conditions for Stabilization of Photosynthetic Activities

Biochemistry Department, The Weizmann Institute of Science, Rehovot, Israel

Preservation of photosynthetic activities (photophosphorylation, electron transport, fluorescence induction, 0.3-second delayed light emission) of isolated broken (class C) chloroplasts by low temperature storage was investigated under a wide range of conditions in order to optimize long time activity retention.

The more labile functions (photophosphorylation and electron transport) required very low temperatures (below –79 C) and relatively high (above 20%, v/v) concentrations of cryoprotectives for satisfactory stabilization. Fluorescence induction and delayed light emission were less sensitive, especially during the 1st month of storage.

Taking into account the effect of cryoprotectives on absolute activities prior to freezing, optimum activity retention was observed with a medium containing ethylene glycol (30%, v/v) and a storage temperature of –100 C or below. In this case, given fast thawing and high chloroplast concentration, practically 100% preservation of all of the photosynthetic activities investigated was obtained for at least 10 months, even with very simple freezing and storage procedures.

The same optimal medium at somewhat higher temperatures (–79 C and to a lesser extent at –41 C) caused a dramatic uncoupling effect: photophosphorylation was inhibited in a few hours, while electron transport increased 3- to 5-fold. The enhanced electron transport was stable for almost a month and then declined sharply. This uncoupling effect was specific only to ethylene glycol.